Removal of sulfuric acid compounds

ABSTRACT

Sulfuric acid compounds are removed from reaction mixtures by a reaction with unsaturated terpene compounds or with polybutadiene at elevated temperatures whereby products of reduction are formed which are volatilizable at the temperature of reaction and by expelling said products of reduction from the reaction mixture. Thus a product being substantially free from a sulfur content is obtained.

This is a continuation-in-part-application of application Ser. No.776,249, filed Nov. 15, 1968 which has been abandoned.

This invention relates to a process for the reductive removal of asulfuric acid compound, i.e. of sulfuric acid and its acid-reactingderivatives from reaction mixtures.

Unsaturated terpene compounds such as terpentine oil, naturallyoccurring resinic acids or natural rubber are frequently reacted in thepresence of sulfuric acid and acid-reacting derivatives thereof, forexample in isomerisation, disproportionation and polymerisationprocesses, as well as in reactions involving the addition of phenoliccompounds to terpenes. For example naturally occurring resinic acids ortheir esters may be dimerised or reacted with phenols in the presence ofsulfuric acid and synthetic or naturally occurring rubber may becyclised in the presence of sulfuric acid. In such processes sulfuricacid or acid-reacting derivatives thereof are removed from the reactionmedia after the desired reaction has taken place by washing, usuallyafter neutralisation e.g. with bicarbonate or carbonate. If solventshave been used or if volatile components have been formed these areusually removed by heat treatment and if the reaction product ishigh-melting and/or viscous the washing process itself may require theuse of solvents which, in turn, must be distilled off. In any case theworking up of a reaction product by means of a washing process isusually inconvenient.

We have now found a simple process, which does not involve a washing orneutralisation step, by which sulfuric acid and acid-reactingderivatives thereof can be removed from reaction mixtures containingthem.

According to the present invention therefore there is provided a processof removing discoloring amounts of color forming sulfur compounds fromthe reaction products of a reaction mixture containing an acid-reactingsulfur-containing ingredient as a reagent, reaction product or catalyst,selected from the group consisting of sulfuric acid, sulfuric acidesters of olefins and sulfuric acid and sulfonic acids having at mosttwo sulfonic acid groups, the improvement comprising reacting thereactants in the reaction mixture, then reacting said acid reactingsulfur containing ingredient in the reacted mixture with an amount of anolefinic unsaturated terpene or of polybutadiene which amount issufficient to react with and reduce all of said acid-reacting sulfurcontaining ingredients and form volatilizable reduction products of allof said sulfur containing ingredients and then heating and maintainingthe reacted mixture until no more gaseous products are formed at atemperature between about ambient temperature and about 320° C that issufficient to substantially reduce, voltatilize and remove all of saidsulfur containing reduction products to thereby provide an ultimatereaction product that is free of strong discoloring amounts of saidcolor forming sulfur compounds.

Preferably the process of the invention is applied to reaction mixtureswhich contain unsaturated terpenes or polybutadienes. Such reactionmixtures which after the addition of sulfuric acid or of derivativesthereof generally become dark brown or even black are according to theinvention heated to a temperature which is higher than that hithertoused in such reactions, and maintained at such temperatures until thereduction is substantially terminated. Thus the present reaction is alsosuitable for the removal of sulfuric acid or its derivatives such assulfonic acids or sulfuric acid esters from reaction products, which perse do not contain unsaturated terpenes, but from which such sulfurcontaining compounds cannot be removed without difficulty or from whichsuch compounds can only be removed while impairing the properties of thefinal product. In this reaction there are formed large quantities ofgaseous compounds, particularly sulfur dioxide, but also hydrogensulphide. However there may also be formed minor amounts of sulfur.Water is a further reaction product. All these reaction products can bya proper conduction of the temperature be evaporated at ordinarypressure, if desired also at reduced or increased pressure, or in acurrent of an inert gas. Any elementary sulfur which is formed is alsoevaporated and may be condensed in a cooler. At the same time almost nodiscoloration of the final reaction mixture occurs, although initially asubstantial discoloration is caused by the sulfuric acid and its acidderivatives. Accordingly the final products are very often even lighterin color than those obtained according to the hitherto used processincluding a washing and/or neutralisation procedure.

Acid-reacting derivatives of sulfuric acid include those containing anSO₃ group in a form such that they relatively fairly decompose atelevated temperatures, generally above 120° C. Such derivatives includeparticularly those of sulfuric acid and aromatic compounds such ashydrocarbons, unsubstituted or substituted phenols having up to 18carbon atoms, and/or sulfonic acids formed from carboxylic acids as wellas sulfonic acids and sulfuric acid esters formed from sulfuric acid andnon-aromatic compounds, particularly unsaturated non-aromatic compoundse.g. olefins. Such suitable unsubstituted or substituted phenols havingup to 18 carbon atoms are for example alkylphenols or arylphenols suchas iso-propylphenol, tert-butylphenol, nonylphenol, dodecylphenol,styrenated phenol, the various phenylphenols, halogenophenols andnitrophenols. Sulfonic acids formed from carboxylic acids are forexample the various mono- or dicarboxylic benzene sulfonic acids,sulfosalicylic acid, sulfo-anthranilic acid.

The acid-reacting derivatives of sulfuric acid can either be added tothe reaction mixture in pure form or be produced from sulfuric acid andanother reagent in a connected process, possibly in the form of a stockmixture. In the latter case there are suitably used compounds which areper se contained in the reaction mixture, or other compounds, such asthose recited in the preceding paragraph. It is also possible to firstlyreact colophony with sulfuric acid (cf Example 17) and the add phenol orany other reaction component.

Other sulfuric acid-deprivatives which may reductively be removed fromreaction mixtures by the process according to the invention include o-and p- phenol-sulfonic acid, the various phenol disulfonic acids oralkyl phenol sulfonic acids such as o- and p- cresol- mono- ordi-sulfonic acid, in which SO₃ H groups are adjacent to the OH- group,butyl, octyl and dodecyl phenol sulfonic acids, sulfonic acids ofaryl-substituted phenols, such as phenyl phenols, sulfonic acids ofpolyhydric phenols such as resorcinol, sulfonic acids of phenol-aldehydecondensates such as of dihydroxydiphenyl methanes or of the highercondensates commonly called novolaks, o- and p- halogeno phenol sulfonicacids or disulfonic acids, 2,4-dichlorophenol sulfonic acid,p-toluenesulfonic acid, the various sulfonic acids of the xylenes,mesitylene, diphenyl and naphthalene, halogeno sulfonic acids such aschloro- and bromosulfonic acid, sulfuric acid esters obtained by theaddition of sulfuric acid to olefines, e.g. cyclic and acyclic terpenesor sulfonic acids of these terpenes.

During the process according to the invention sulfuric acid is reducedto SO₂, S or even H₂ S and this reduction may concur with adehydrogenation of the reactants. Thus the sulfur compounds formed fromthe sulfuric acid and acid derivatives thereof as well of theprereaction-products -- such as those of sulfuric acid and colophony --by scission and reduction may be eliminated on heating due to the factthat they are volatilizable which term is intended to include gaseousproducts. Consequently, no neutralisation and/or washing process isnecessary, nor is any steam treatment and even distillation underreduced pressure to remove final traces of acid may be dispensed with.The products obtained react almost neutral provided no acidity isactually introduced into the end product, e.g. by other functionalgroups contained in the starting material. The process according to theinvention is successful with all reaction products built up fromterpenes or from polybutadienes, inasfar as they both still containolefinic double bonds. The term "terpene compounds" as used hereinincludes polymeric forms of isoprene or derivatives thereof irrespectiveof whether or not they are naturally occurring such as resinic acids,natural rubber or terpentine oil, or synthetic such as polyisoprene andwhether they are cyclic or acyclic and furthermore Diels-Alder reactionproducts of colophony with dienophilic carboxylic acids or derivativessuch as maleic anhydride or esterification products thereof. Alsocolophony may be dehydrogenated at high temperatures by means ofconcentrated sulfuric acid and again light resins are obtained. Thepolybutadienes comprise high -- and preferably low -- molecularpolybutadienes, the latter having an average molecular weight of up to50,000, preferably up to 15,000.

The mixtures can also, if desired, contain other components, such assolvents, mono- or polyhydric, if desired polynuclear phenols orderivatives thereof, and fatty oils. An important application of thepresent invention is in processes where phenol and/or substitutedphenols are present as reaction components and/or solvents. Exemplary ofsuch phenols are phenol, resorcinol, the various cresols, xylenols orother alkyl phenols such as butyl-, octyl-, nonyl-, dodecylphenol,naphthols, phenol etheres such as anisole, chlorophenols, phenyl phenolsor other aryl phenols, phenol carboxylic acids and bisphenols, such asbis-(4-hydroxyphenyl)-alkanes, e.g. bis-(4-hydroxyphenyl)-propane andits higher or lower homologs such as bis-(4-hydroxyphenyl-)methane ornovolak derivatives of phenols containing at least three nuclei. Thereare numerous reactions during which sulphuric acid or acid-reactingderivatives thereof are added, e.g. as reagents or catalysts and inwhich the removal of the sulfuric acid or derivative thereof is at leastdesirable. This can be achieved according to the invention by, e.g. atthe end of the main reaction, adding suitable unsaturated terpenecompounds in such quantities as are necessary for the reduction of thesulfuric acid components by heating.

The process according to the invention can be used on reaction productsobtained by very different routes e.g. condensation, polymerisation oralkylation, the latter particularly with the formation of C-C or C-Nbonds, if desired also with ester formation. It is particularlyrecommended when the separation of the acid from the reaction product isnecessary but can be achieved only with difficulty by the usual methods.In particular sulfonic acid groups or sulfuric acid esters which areformed during the main reaction as undesired by-products may be easilyremoved by this process. For example, the sulfuric acid used for thecatalytic alkylation of phenol or phenol derivatives with olefines, e.g.cycloolefines, such as with diisobutylene, cyclohexene, styrene (on theolefinic group) and the like, can be eliminated without a washing orneutralisation process by reduction at an elevated temperature in anafter-treatment with colophony, pinene, dipentene or other suitableterpenes or with polybutadienes. The process is also applicable to thereaction products of phenols with unsaturated compounds having little orno reductive action on the sulfuric acid or sulfonic acid components,e.g. addition products of phenols with unsaturated esters, fatty acids,etc.

The present process may also be used in the purification of the productsobtained during the reaction of phenols or phenol derivatives withaldehydes, in particular formaldehyde, or with ketones or compoundswhich split off such carbonyl compounds under the conditions of thereaction. These reactions may be relatively slow due to a smallreactivity of the phenols or the phenol derivatives and/or the carbonylcompound and it is therefore desirable to employ sulfuric acid orsulfonic acids as condensing agents. When using sulfuric acid there is adanger that it may become partly incorporated in the condensationproduct in the form of sulfonic acids or sulfuric acid esters and theseproducts may prove to be difficult to remove by the usual methods sothat during the further working up or processing of the products theymay have an undesirable effect e.g. on heating they may initiatedecomposition and cause a dark discoloration. To alleviate thesedifficulties many of these processes have hitherto often been performedwith concentrated hydrochloric acid which, however, requiredcorrosion-resistant, and therefore costly, reaction vessels. The presentprocess simplifies working and it is still possible to obtain light andstable end products.

Illustrative of slowly reacting phenols are e.g. longchained alkylphenols with a carbon chain of 3 to 15 C-atoms such as p-tert-butyl-,p-diisobutyl or p-triisobutyl phenyl, halogenophenols such as mono- ordichloro- or mono- or dibromo-phenols, aryl phenols in particular p-arylphenols such as p-phenyl phenol, phenols containing several rings suchas naphthols or bisphenols such as p,p'-dihydroxydiphenyl alkanes,phenol ethers with saturated or unsaturated aliphatic groups having 1-12C-atoms and also having COOH- or OH- groups such as phenetol, phenoxyacetic acid, diphenyl glycerol ether, phenyl allyl ether, etc. or phenolethers with aromatic radicals.

Illustrative of slowly reacting carbonyl compounds are, in particular,those having 2 to 9 C-atoms such as acetaldehyde, propionaldehyde,butyr- or isobutyraldehyde, acetone, cyclohexanone or acetophenone.Thus, the reaction product prepared from 2 mols of phenol and 1 mol ofacetone using sulfuric acid, consisting essentially ofbis-(4-hydroxyphenyl)-propane (diane) cannot be heated above the meltingpoint or distilled without decomposition even after careful washing withwater because traces of unremoved sulfonic acids cause a decompositionof the diane accompanied by darkening. On distillation in the presenceof colophony or other terpenes such as pinene such decomposition doesnot occur and a light product is obtained which can be distilled withoutdecomposition under reduced pressure.

Other reactions in which sulfuric or sulfonic acid type reagents orby-products may be removed by thermal after-treatment with terpenecompounds or with polybutadiene include the polymerisation of olefinesperformed with sulfuric acid, such as the preparation ofcoumarone-indene resins. In this reaction there may be discoloration ofthe product due to the incorporation of sulfonic acids which have alsoemulsifying properties (cf. J. Scheiber, Chemie und Technologie derkuenstlichen Harze, 1943, p.267 ff). However, neutralisation and washingof the sulfuric acid components can be completely avoided and relativelylight end products result if a terpene or polybutadiene are added afterpolymerisation has been completed and the volatile, nonpolymerisedcomponents are distilled off at normal pressure.

For the reductive removal of sulfuric acid or its acid-reactingderivatives the above-mentioned terpene compounds or polybutadiene areparticularly suited and of these naturally occurring resinic acids arepreferred. The quantity of terpene compounds or of the polybutadieneemployed is preferably just sufficient to reduce the catalyst but not somuch as to have a negative influence on the properties of thecondensation products. It is generally between two and ten times theweight of sulfuric acid or sulfuric acid derivative present and thisgenerally presents 3 - 30 % by weight of the condensate. However largerquantities of terpene compounds or of polybutadiene can also be addedwithout any harmful effect.

If by the addition of a terpene sulfuric acid or the derivatives thereofhave been removed from synthetic resins which per se did not containterpenes or polybutadienes, but only the sulfuric acid or itsderivative, the final products very often have improved properties dueto the after-treatment with the terpenes or the polybutadienes. Thusproducts may be obtained which are not only light in color, but havealso a higher melting point and an improved solubility than thoseproducts which have been produced from equal amounts of the samestarting materials, but have been worked up with the aid of a washingprocedure. The present process is generally performed in the temperaturerange from 50° to 320° C, preferably from 170° to 280° C. However, itwill be appreciated that in some reactions dependent on the reactioncomponents decomposition begins already at fairly low temperatures e.g.room temperature, and that no temperature is applied at which theproduct would even be decomposed in the absence of sulfuric acid or itsderivatives, since clearly in such cases the temperatures cited aboveare unsuitable. In general however, for complete removal of the SO₃grouping and/or in order to obtain products which are not discolored,temperatures of at least 170° C are necessary. It is also possible towork under reduced or, less advantageously, under increased pressure.Thus the temperature varies dependent on the nature of the reactionmixture at which the reductive decomposition of the sulfuric acid orsulfuric acid derivative begins. In reactions with resinic acidsreductive decomposition begins below about 80° - 100° C, e.g. at 50° C,is greatly intensified between 120° and 170° C and is completed at evenhigher temperatures. In other cases e.g. in reactions of polyisoprene inthe presence of phenols or in reactions of terpene hydrocarbons, thereductive decomposition only begins at above 150° C. Of course thereductive elimination of sulfuric acid or sulfuric acid derivativesaccording to the invention also depends on their quantity.

It was surprising and is advantageous that the thermal, reductiveremoval of sulfuric acid or sulfuric acid derivatives occurs withoutdisturbing secondary reactions such as e.g. often occur with resinicacids in the form of decarboxylation of the carboxyl group.

The initially cited technical processes as well as other similarprocesses using diluted or concentrated sulfuric acid as the reagent,can be performed much more easily using the process according to thepresent invention, and the products prepared may be valuableintermediates or final products e.g. varnish raw materials. In addition,they are suitable for known applications e.g. for the preparation ofcoatings, adhesives and printing inks.

The following Examples, substantially free of aldehydes, wherein partsreferred to are parts by weight, illustrate the invention. In theExamples melting points are determined by using a capillary tube.

EXAMPLE 1

300 parts of phenol are mixed with 3 parts of concentrated sulphuricacid and then at 50° C over a period of 3 hours 300 parts of terpentineoil are added dropwise in such a way that, as a result of the exothermalreaction, the temperature rises continuously to 80° C. Over a period offive hours the temperature is slowly raised to 170° C then held at thistemperature until the reaction mixture becomes clear and virtually freefrom sulphur dioxide. The temperature is raised to 220° C and excessphenol is distilled off then, over a further two hours, the temperatureis raised to 260° C at which temperature only very slight transformationof the resin occurs. 350 parts of a light yellow terpene-phenol resinmelting at 70° C is obtained. A solution in a mixture of equal parts byvolume of toluene and ethanol shows an almost neutral reaction withmethyl orange indicating that the product is free from sulphuric acid.

EXAMPLE 2

300 parts of comminuted polyisoprene and 10 parts of concentratedsulphuric acid are added to 300 parts of phenol at 170° C and themixture is kept at this temperature for seven hours. The polyisoprenegradually goes into solution and sulphur dioxide is evolved. Aninitially brown-black coloured reaction mixture becomes considerablylighter during this time. Subsequently excess phenol is distilled off attemperatures of up to 260° C and 330 parts of product are obtained whichproduct may be used as a raw material in the manufacture of varnish. Asolution in a mixture of equal parts by volume of toluene and ethanolshows a neutral reaction with methyl orange.

If in place of synthetic polyisoprene natural rubber is used and/or thecyclisation is performed in the presence of another solvent such as analiphatic, aromatic or halogenated hydrocarbon instead of phenol,products free from sulphuric acid are also obtained.

EXAMPLE 3

600 parts of ester gum and 300 parts of phenol are mixed at 80° C with12.5 parts of concentrated sulphuric acid. The temperature is raised toabout 90° C, the mixture darkens and some sulphur dioxide is evolved. Onfurther heating to 180° C the bulk of the sulphur dioxide is evolved.After distilling off excess phenol in vacuo 680 parts of anamber-coloured resin, free from sulphuric acid having a melting point of115° C are obtained.

EXAMPLE 4

650 parts of a reaction product of 1400 parts of colophony with 300parts of maleic anhydride and 250 parts of phenol are mixed at 80° Cwith 15 parts of concentrated sulphuric acid. The temperature risesslightly, the mixture darkens and some sulphur dioxide is evolved. Thegas evolution ceases when the temperature is raised to 180° C. Afterdistilling off excess phenol 670 parts of a yellow resin free fromsulphuric acid are left with a melting point of 117° C.

EXAMPLE 5

300 parts of colophony are dissolved in 100 parts of toluene at 70° C,then cooled to -10° C. 25 parts of concentrated sulphuric acid are addeddropwise over a period of 1 hour in a manner such that the temperaturedoes not rise above 40° C then the mixture is held below 40° C. foreight hours. During this time polymerisation occurs accompanied by theevolution of sulphur dioxide. The temperature is raised to 220° C andthe reaction product is restored almost to its original lightness. Themelting point of the resin formed is about 25° C higher than that of theoriginal colophony and the acid number is 146 as compared with aninitial value of 165. The product shows an almost neutral reaction withmethyl orange.

EXAMPLE 6

600 parts of colophony and 220 parts of a technical mixture of cresolscontaining mainly m-cresol are mixed at 80° C with 12.5 parts ofconcentrated sulphuric acid. The temperature is allowed to rise to 95° Cdue to the exothermal reaction and darkening occurs. On heating to 150°C there is considerable evolution of sulphur dioxide and the reactionmixture lightens almost to its original colour. Excess m-cresol isdistilled off in vacuo and 660 parts of a very light resin, free fromsulphuric acid melting at 113° C is obtained. If a technical cresolmixture having a major proportion of p-cresol is used a light yellowresin is also obtained.

EXAMPLE 7

300 parts of colophony and 130 parts of o-chlorophenol are mixed with 6parts of concentrated sulphuric acid at 80° C. The temperature isallowed to rise to 90° C, the mixture darkens and some evolution ofsulphur dioxide occurs. The bulk of the sulphur dioxide is evolved at150° C, at which temperature the reaction mixture lightens to almost itsoriginal colour. Unreacted o-chlorophenol is distilled off in vacuo and310 parts of a yellow resin, free from sulphuric acid, and having amelting point of 89° C are obtained.

EXAMPLE 8

600 parts of colophony and 300 parts of o-sec. butyl phenol are mixedwith 12.5 parts of concentrated sulphuric acid, the mixture darkens andthe temperature rises to 90° C. The temperature is raised to 150° C andsulphur dioxide is evolved then excess o-sec.-butyl phenol is removedfrom the clear mixture by distillation in vacuo. 660 parts of resin freefrom sulphuric acid are obtained having a melting point of 105° C. Ifinstead of the o-sec-butyl phenol the same quantity of p-tert-butylphenol is reacted, an amber-coloured resin is obtained. If the colophonyis reacted in analogous manner with 200 parts of octyl or nonyl phenollight resins are again obtained.

EXAMPLE 9

600 parts of colophony and 250 parts of 1,2,4-xylenol are mixed with 13parts of concentrated sulphuric acid at 80° C. The temperature isallowed to rise to 90° C, the mixture darkens and some evolution ofsulphur dioxide occurs. The bulk of the sulphur dioxide is evolved at150° C and excess xylenol is distilled off in vacuo to yield 620 partsof a golden-yellow resin free from sulphuric acid melting at 102° C.

EXAMPLE 10

600 parts of colophony and 110 parts of resorcinol are slowly mixed at100° C with 2.5 parts of concentrated sulphuric acid. The mixturedarkens and the temperature rises to 122° C due to the exothermalreaction at which temperature the reaction mixture becomes clear andvery viscous. The bulk of the sulphur dioxide is evolved at 140° C and620 parts of a light resin free from sulphuric acid and melting at 122°C is obtained.

EXAMPLE 11

300 parts of colophony and 145 parts of α-naphthol are mixed with 6parts of concentrated sulphuric acid at 80° C. The mixture darkens andthe temperature is allowed to rise to 100° C at which temperature thereaction mixture becomes very viscous. Evolution of sulphur dioxidecommences at 90° C. The resulting resin lightens during distillation invacuo to yield 325 parts of a product melting at 113° C.

EXAMPLE 12

600 parts of colophony and 230 parts of bisphenol A[bis-(4-hydroxyphenyl)-propane] are mixed at 135° C with 2.5 parts ofconcentrated sulphuric acid. The mixture darkens and, accompanied bypronounced evolution of sulphur dioxide, the temperature is allowed torise to 140° C. The bulk of the sulphur dioxide is evolved at 150° C.After distillation in vacuo 620 parts of a very light reaction productfree from sulphuric acid are obtained melting at 112° C.

EXAMPLE 13

600 parrts of colophony and 320 parts of a novolak (prepared in theusual manner from 1 mol of phenol and 0.8 mol of formaldehyde) are mixedat 120° C with 10 parts of concentrated sulphuric acid. The temperaturerises to 135° C due to the exothermal reaction at which temperature thereaction mixture becomes dark and viscous. At 180° and 200° C pronouncedsulphur dioxide evolution occurs and the resin becomes light. Afterdistillation in vacuo 800 parts of a product free from sulphur dioxidemelting at 130° C are obtained.

EXAMPLE 14

600 parts of colophony and 220 parts of anisole are mixed with 5 partsof concentrated sulphuric acid at 80° C. The mixture darkens and thetemperature is allowed to rise to 90° C. The temperature is raised to150° C and maintained at this level until the evolution of sulphurdioxide which starts at about 100° C ceases. Excess anisole is distilledoff in vacuo to yield 640 parts of a light resin free from sulphuricacid and having a melting point of 118° C.

EXAMPLE 15

300 parts of phenol are mixed with 3 parts of o-chlorophenol sulphonicacid. Then over a period of three hours at 50° C 600 parts of terpentineoil are added dropwise so that, due to the exothermal reaction, thetemperature rises continuously to 100° C. Over a further three hours thetemperature is raised slowly to 190° C, and this temperature ismaintained until the reaction mixture becomes clear and evolution ofsulphur dioxide ceases. Excess phenol is then distilled off at 220° Cand over a further two hours the temperature is raised to 270° C atwhich temperature the resin is formed. 700 parts of a yellowterpene-phenol resin melting at 70° C are obtained. A solution in amixture of the same parts by volume of toluene and methanol shows analmost neutral reaction with methyl orange indicating that the productis free from o-chlorophenol-sulphonic acid.

EXAMPLE 16

300 parts of comminuted polyisoprene and 5 parts of a mixture of o- andp-phenol sulphonic acid are added to 300 parts of phenol at 175° C andthis temperature is maintained for 8 hours. The polyisoprene graduallypasses into solution and sulphur dioxide is evolved. The initiallybrown-black coloured mixture becomes ligher and subsequently excessphenol is distilled off at up to 260° C. 330 parts of a produt suitablefor use as a raw material in the manufacture of varnish are obtained. Asolution in a mixture of the same parts by volume of toluene and ethanolshows a neutral reaction with methyl orange.

If natural rubber is used instead of polyisoprene and/or the cyclisationis performed in the presence of another solvent such as an aliphatic,aromatic or halogenated hydrocarbon instead of phenol, products freefrom phenolsulphonic acid are again obtained.

EXAMPLE 17

12 parts of concentrated sulphuric acid are slowly added to 600 parts ofcolophony at 100° C. The mixture darkens and the temperature rises, dueto the exothermal reaction, to 135° C at which temperature the reactionmixture becomes more viscous. Subsequently 280 parts of phenol heated to60° C are added and the mixture is maintained for two hours at 120° C.On further heating at 170° to 190° C extensive evolution of sulphurdioxide occurs and at 220° to 240° C the reaction mixture clears. Afterdistillation in vacuo 700 parts of a yellow resin having a melting pointof 125° C are obtained.

EXAMPLE 18

600 parts of colophony and 320 parts of a novolak (prepared in the usualmanner from 1 mol of phenol and 0.8 mol of formaldehyde) are mixed at120° C with 10 parts of chlorosulphonic acid. The mixture darkens andthe temperature rises, due to the exothermal reaction, to 130° C atwhich temperature the reaction mixture becomes more viscous. Pronouncedevolution of sulphur dioxide occurs when the temperature is raised to180° to 200° C and the reaction mixture becomes lighter. Afterdistillation in vacuo 800 parts of an amber-coloured resin are obtained.The product is free from chlorosulphonic acid and melts at 130° C.

EXAMPLE 19

752 parts of phenol, 548 parts of isobutyraldehyde and 4 parts ofsulphuric acid are boiled for eight hours. The temperature rises overtwo hours from 68° C to 110° C. After 8 hours the isobutyraldehydecontent is to 1.7%. 20 parts of balsam colophony are added and thevolatile components are distilled off. The temperature rises to 260° Cand above 180° C the black-brown coloured mixture becomes much lighter.On reaching 260° C the reaction mixture is cooled and 1,108 parts of anamber-coloured resin having a colour value of 30-35 (according toHellige) and a melting point of 85° C are obtained. A solution in amixture of equal parts toluene and ethanol shows a neutral reaction withmethyl orange.

EXAMPLE 20

300 parts of p-tert-butyl phenol are melted and 2 parts ofphenol-sulphonic acid are added. 100 parts of acrolein are addeddropwise at 105° C and 25 parts of tallcolophony are added to the blackcoloured mixture. The mixture is stirred for a further hour at 110° Cand the volatile components are distilled off at atmospheric pressure.The mixture becomes lighter at 120° C at which temperature evolution ofsulphur dioxide begins and, on reaching 260° C the evolution of sulphurdioxide has ceased. The mixture is heated to 290° C and then cooled to180° C in the presence of an inert gas. 320 parts of a light resinhaving a colour value between 20 and 30 (according to Hellige) areobtained. The solution of the resin in a mixture of equal parts oftoluene and ethanol shows a neutral reaction with methyl orange.

EXAMPLE 21

188 parts of phenol and 63 parts of acetone are condensed in 800 partsof 72% sulphuric acid at 40° C for 30 hours, then crystalline separationof the bis-(4-hydroxyphenyl)-propane formed commences. The crystalformation is favored by cooling and the addition of 10 parts of toluene.The crystals are filtered off, thoroughly washed with water and dried inan air-drying cubicle at 85° C. The product obtained has a melting pointof 153° C. After repeated washing, even accompanied by the addition ofammonia, they are found to be not completely free from the sulphonicacids formed, which e.g. on distillation at 15 to 20 Torr causeconsiderable decomposition and the formation of large amounts ofresidue. The distillate obtained is an intense orange-yellow colour andcontains besides other products much mononuclear phenol. In addition,large amount of an almost black residue are left behind.

If 5% colophony is added to the raw material to be distilled it can bedistilled practically undecomposed. The distillate is almost colourlessand consists of pure bis-(4-hydroxyphenyl)-propane. The approximately 8%residue left behind is also much lighter than the residue producedwithout the addition of colophony. In the same waybis-(4-hydroxyphenyl)-propane containing sulphonic acid can be mixedwith 5% α-pinene instead of 5% colophony, and this is then distilled at15 to 20 Torr. Once again a very pure distillate of thebis-(4-hydroxyphenyl)-propane is obtained and less than 5% residue isleft behind.

EXAMPLE 22

6 g of concentrated sulphuric acid are added to 94 g of phenol. Then 104g of styrene are gradually added dropwise firstly at 50° C, later-on ata higher temperature. The reaction is exothermic and towards the end ofthe addition a temperature of 115° C is reached. During the furtherheating the reaction mixture becomes dark. Now 20 to 60 g of colophonyare added in order to remove the catalyst. Within the temperature rangeof 140° to 200° C an intensive formation of sulphur dioxide takes placeand at the same time the product becomes lighter. After distilling offonly partially reacted components at a temperature of about 260° C, 160g of a soft yellow-brown product which is used for further reactions areobtained.

EXAMPLE 23

A product is prepared from 100 g of phenol and 111 g of styrene with 2 gof 20% oleum according to example 22 and the product is further reactedwith 91 g of 30% formaldehyde solution to form a styrene containingnovolak which has a dark color. Now 20 g of colophony are added in orderto remove the sulphuric acid catalyst. The reductive decomposition ofthe oleum essentially takes place in the temperature range between 140°and 220° C in which the volatile parts are distilled off at 260° C. 240g of a yellow solid resin with a melting point of 73° C are obtained.

EXAMPLE 24

6 g of concentrated sulphuric acid are added to 94 g of phenol at 50° C.Then 68 g of isoprene are added dropwise and in the course of theexothermic reaction the temperature is increased to 140° C. Between 130°and 140° C there is a weak formation of sulphur dioxide which becomesintensive by addition of 50 g of colophony and which is finallycompleted at higher temperatures between 220° and 240° C by distillationoff the volatile parts. 170 g of a solid resin with a melting point of65° C are obtained.

EXAMPLE 25

12 g of concentrated p-phenol sulphonic acid are added to 94 g ofphenol. Then 112 g of diisobutylene are dropwise added which react in anexothermic reaction under dark coloration. After adding 20 to 60 g ofcolophony an intensive formation of sulfur dioxide takes place alreadyat 120° C which is finished at 180° C. After the processing in vacuum at260° C 180 g of an amber colored product with a melting point of 64° Care obtained.

EXAMPLE 26

4 g of concentrated sulphuric acid are added to 94 g of phenol. Thenbeginning with a temperature of 50° C 264 g of dicyclopentadiene areadded dropwise. The reaction is exothermic under dark coloration. Now 50g of colophony are added in order to remove the catalyst. At the sametime with the formation of volatile products the product becomeslighter. After processing in vacuum at 240 to 260° C in distilling offthe low molecular parts 250 g of a resin with a melting point of 130° Care obtained.

EXAMPLE 27

6 g of concentrated sulphuric acid are added to 94 g of phenol. Then 120g of a mixture of various petroleum fractions with a boiling point of140° to 195° C, esentially consisting of a mixture of hydrocarbonsubstituted cyclic hydrocarbons, especially aromatic ones, are addeddropwise. By addition of 20 g of synthetic polyisoprene which isdecomposed by the sulphuric acid and which has a strong reduction effectthe catalyst is removed from the obtained viscous product by adistillation in vacuum for 3 hours at 260° C. 185 g of a soft plasticproduct are obtained.

EXAMPLE 28

6 g of p-phenol sulphonic acid are added to 94 g of phenol. Then 280 gof dehydrogenated castor oil fatty acid are added dropwise within 1 hourat 50° C. The separation of the catalyst by reduction is effected byadding 50 g of colophony. After processing in vacuum for 5 hours at 260°C 380 g of a dark yellow high viscous product are obtained.

EXAMPLE 29

2 parts of concentrated sulphuric acid are slowly added to 200 parts ofphenol at a temperature of 50° C. Then 100 parts of a low molecularpolybutadiene (iodine number 450, average molecular weight 3200) areadded dropwise within 90 minutes. Already at the beginning reaction themixture becomes black-brown. The reaction mixture gradually becomes moreand more viscous under a weak exothermic reaction. Under heating at atemperature of 90° C the reaction becomes more exothermic underformation of sulphur dioxide and under a temperature increase which mayreach 160° C. Then the reaction mixture begins to become lighter at 180°C. The heat treatment is continued in vacuum until 230° C and an ambercolored resin is obtained with a yield of 137%, referred to the startinglow molecular polybutadiene. Melting point of the resin 128° C,OH-number 160. A resin with the same properties is obtained if insteadof the above-mentioned polybutadiene a polybutadiene with an averagemolecular weight of 1,400 and a iodine number of 450 is used as astarting material.

EXAMPLE 30

2 parts of phenol sulphonic acid (65%) are added to a mixture consistingof 300 parts of phenol, 100 parts of low molecular polybutadiene and 10parts of colophony at a temperature of 70° C. The mixture is processedaccording to example 29, however the reaction mixture is heated to 260°C instead of 230° C. A light colored resin with a color number of 20 isobtained with a yield of about 140%, referred to the total weight of thestarting colophony and low molecular polybutadiene. It has a meltingpoint of 128° C and a viscosity (50% solution in toluene/20° C) of 2,760cP, a OH-number of 112 and an acid number of 5. The polybutadiene whichis used in this example is the same as in example 29 and it may also besubstituted by the polybutadiene as mentioned in the last paragraph ofexample 29.

EXAMPLE 31

0,6 parts of a 65% phenol sulphonic acid are added to a mixture of 340parts of phenol formaldehyde resin and 46 parts of p-formaldehyde at 40°C. Then the temperature is increased to 58° C within 30 minutes. Theexothermic reaction begins at this temperature after some time andcauses an increase of the temperature up to 105° C. After refluxing forthree hours the temperature is increased to 150° C under reducedpressure. After this treatment a novolak is obtained which has astrongly acid reaction with methylorange. In order to remove the phenolsulphonic acid 15 parts of a low molecular polybutadiene oil (iodinenumber 450, average molecular weight of about 1,400) are added and themixture is heated to 170° C. At this temperature an intensive formationof sulphur dioxide begins and the reaction mixture changes its colorfrom slightly red to pale yellow. The reaction mixture is then furtherheated to 240° C. Having reached this temperature the reaction producthas a neutral reaction which shows that it is practically free of thephenol sulphonic acid. 263 parts of a resin with a melting point of 72°C are obtained. The yield is 73%.

It is not intended that the examples given herein should be construed tolimit the invention thereto, but rather they are submitted to illustratesome of the specific embodiments of the invention. Resort may be had tovarious modifications and variations of the present invention withoutdeparting from the spirit of the discovery or the scope of the appendedclaims.

What is claimed is:
 1. A process for removing discoloring amounts ofcolor forming sulfur compounds from the reaction products of a reactionmixture containing a terpene reduceable acid-reacting sulfur-containingingredient as a reagent, reaction product or catalyst, the improvementcomprising (1) reacting the reactants in the reaction mixture, (2) thenreacting said acid reacting sulfur containing ingredient in the reactedmixture with an amount of an olefinic unsaturated terbene which issufficient to react with and reduce all of said acid-reacting sulfurcontaining ingredients and form volatilizable reduction products of allof said sulfur containing ingredients and (3) then heating andmaintaining the reacted mixture until no more gaseous products areformed at a temperature between about ambient temperature and about 320°C that is sufficient to substantially reduce, volatilize and remove allof said sulfur containing reduction products to thereby provide anultimate reaction product that is free of strong discoloring amounts ofsaid color forming sulfur compounds.
 2. The process of claim 1, in whichsaid reaction mass is free of unreacted aldehydes.
 3. The process ofclaim 1 in which said olefinic unsaturated terpene is selected from thegroup consisting of isoprene, polyisoprene, resinic acids, naturalrubber, terpentine oil, colophony, Diels-Alder reaction products ofcolophony with dienophilic carboxylic acids, Diels-Alder reactionproducts of colophony with esters of dienophilic carboxylic acid andlight resins derived from colophony dehydrogenated with concentratedsulfuric acid.
 4. The process of claim 1, in which said reducing andvolatilizing temperature is from 170° to 280° C.
 5. The process of claim1, in which said reaction mixture contains an unsaturated terpenereactant.
 6. The process of claim 1, in which the quantity of saidolefinic unsaturated terpene added to reduce said sulfur compounds isbetween 2 to 10 times the weight of said sulfur compounds present insaid reaction mixture.
 7. The process of claim 1, in which the quantityof said olefinic unsaturated terpene added to reduce said sulfurcompounds is between 3 to 30% by weight of the weight of the terpenecontaining reaction product.
 8. The process of claim 1 in which saidreducing and volatilizing temperatures are higher than the reactiontemperature between said sulfur containing ingredients and said olefinicunsaturated terpene.
 9. The process of claim 1, in which said olefinicunsaturated terpene is a synthetic rubber containing isoprene units. 10.The process of claim 1, in which said acid-reacting sulfur containingingredient is selected from the group consisting of sulfuric acid,phenol-sulfonic acid, phenol disulfonic acid, cresol sulfonic acid,cresol disulfonic acid, resorcinol sulfonic acid, dihydroxydiphenylmethane sulfonic acid, 2,4-dichlorophenol sulfonic acid, toluenesulfonicacid, xylene sulfonic acid, mesitylene sulfonic acid, diphenyl sulfonicacid, naphthalene sulfonic acid, chlorosulfonic acid, bromosulfonic acidand terpene sulfonic acids.
 11. The process of claim 1, in which saidreaction mixture contains a compound selected from the group consistingof phenol, bisphenol, an alkylphenol having up to 18 carbon atoms,phenyl phenols, phenol carboxylic acids, halogeno phenols, resorcinol,cresol, xylenol, naphthols, anisole and bis-(4-hydroxyphenyl)-alkaneshaving up to 18 carbon atoms.
 12. The process of claim 1, in which saidreaction mixture contains a reactant selected from the group consistingof phenol, phenol sulfonic acid or both and said terpene in an amountbeing sufficient to reduce the sulfur containing ingredient thetemperature at which said sulfur containing ingredient is reduced andsaid reduction product thereof are volatilized is higher than thetemperature at which the reaction between said sulfur containingingredient and said terpene was performed.
 13. The process of claim 1,in which said reactants in the reactant mixture are phenol andterpentine oil, said sulfur containing compound is sulfuric acid andsaid olefinic unsaturated terpene reducing agent is terpentine oil. 14.The process of claim 1, in which said reactants in the reactant mixtureare phenol and ester gum, said sulfur containing compound is sulfuricacid and said olefinic unsaturated terpene reducing agent is ester gum.15. The process of claim 1, in which said reactants in the reactantmixture are phenol, colophony and maleic anhydride, said sulfurcontaining compound is sulfuric acid and said olefinic unsaturatedterpene reducing agent is colophony.
 16. The process of claim 1 in whichsaid reactants in the reactant mixture are colophony and toluene, saidsulfur containing compound is sulfuric acid and said olefinicunsaturated terpene reducing agent is colophony.
 17. The process ofclaim 1 in which said reactants in the reactant mixture are colophonyand cresol, said sulfur containing compound is sulfuric acid and saidolefinic unsaturated terpene reducing agent is colophony.
 18. Theprocess of claim 1 in which said reactants in the reactant mixture arecolophony and o-chlorophenol, said sulfur containing compound issulfuric acid and said olefinic unsaturated terpene reducing agent iscolophony.
 19. The process of claim 1 in which said reactants in thereactant mixture are colophony and o-sec butyl phenol, said sulfurcontaining compound is sulfuric acid and said olefinic unsaturatedterpene reducing agent is colophony.
 20. The process of claim 1 in whichsaid reactants in the reactant mixture are colophony and 1,2,4-xylenol,said sulfur containing compound is sulfuric acid and said olefinicunsaturated terpene reducing agent is colophony.
 21. The process ofclaim 1 in which said reactants in the reactant mixture are colophonyand resorcinol, said sulfur containing compound is sulfuric acid andsaid olefinic unsaturated terpene reducing agent is colophony.
 22. Theprocess of claim 1, in which said reactants in the reactant mixture arecolophony and α-naphthol, said sulfur compound is sulfuric acid and saidolefinic unsaturated terpene reducing agent is colophony.
 23. Theprocess of claim 1, in which said reactants in the reactant mixture arecolophony and bisphenol, said sulfur containing compound is sulfuricacid and said olefinic unsaturated terpene reducing agent is colophony.24. The process of claim 1, in which said reactants in the reactantmixture are colophony and novolak, said sulfur containing compound issulfuric acid and said olefinic unsaturated terpene reducing agent iscolophony.
 25. The process of claim 1, in which said reactants in thereactant mixture are colophony and anisole, said sulfur containingcompound is sulfuric acid and said olefinic unsaturated terpene reducingagent is colophony.
 26. The process of claim 1, in which said reactantsin the reactant mixture are phenol and terpentine oil, said sulfurcontaining compound is O-chlorophenol sulfonic acid, and said olefinicunsaturated terpene reducing agent is terpentine oil.
 27. The process ofclaim 1, in which said reactants in the reactant mixture arepolyisoprene or natural rubber and phenol, said sulfur containingcompound is phenol sulfonic acid, and said olefinic unsaturated terpenereducing agent is cyclized polyisoprene.
 28. The process of claim 1, inwhich said reactants in the reactant mixture are colophony and phenol,said sulfur containing compound is sulfuric acid, and said olefinicunsaturated terpene reducing agent is colophony.
 29. The process ofclaim 1, in which said reactants in the reactant mixture are colophonyand novolak, said sulfur containing compound is chlorosulfonic acid, andsaid olefinic unsaturated terpene reducing agent is colophony.
 30. Theprocess of claim 1, in which said acid-reacting sulfur containingingredient is selected from the group consisting of sulfuric acid,sulfuric acid esters of olefins and sulfuric acid and sulfuric acidcompounds having at most two sulfuric acid groups.
 31. The process ofclaim 30 in which said reducing and volatilizing temperature is170°-280° C.
 32. The process of claim 30, in which said reducing andvolatilizing temperatures are higher than the reaction temperaturebetween said sulfur containing ingredients and said olefinic unsaturatedterpene.